B_(2)O_(3)对含钛高炉渣熔体微观结构与输运性质的影响

Effect of B_2O_(3) on Microstructure and Transport Properties of Melt Titanium-containing Blast Furnace Slag

为高效利用含钛高炉渣中钛元素,采用分子动力学模拟方法研究B_(2)O_(3)含量对CaO-SiO_(2)-B_(2)O_(3)-TiO_(2)系高炉渣微观结构和输运性质的影响。结果表明:B_(2)O_(3)的含量4%时,B—O、Si—O、Ti—O和Ca—O的键长分别为1.34、1.62、1.95和2.24A。渣中存在[SiO_(4)]四面体、[BO_(3)]三角体和[TiO_(6)]八面体稳定结构单元。体系中加入B_(2)O_(3)含量并不会改变O—Si—O、O—B—O和O—Ti—O键角分布情况。随着B_(2)O_(3)的加入,Si—O—Si和B—O—B键角分别从156.12°和148.43°增大到158.17°和157.08°,大部分Ti—O—Ti键角分布在100.48°,小部分Ti—O—Ti键角从140.17°减小到135.53°。随着B_(2)O_(3)含量的增加,B—O—M(Ca、Si、B和Ti)氧连接占比增多,熔体中高配位结构解聚为低配位结构,体系整体聚合度降低,各离子自扩散系数均增大,熔体黏度从0.183 Pa·s降低到0.140 Pa·s。

In order to efficiently utilize titanium element in titanium-containing blast furnace slag,the effects of B_(2)O_(3) content on microstructure and transport properties of CaO-SiO_(2)-B_(2)O_(3)-TiO_(2) series blast furnace slag were studied by molecular dynamics simulation method.The results show that when the content of B_(2)O_(3) is 4%,the bond length of B—O,Si—O,Ti—O and Ca—O is 1.34,1.62,1.95 and 2.24 A,respectively.There are stable structural units of[SiO_(4)]tetrahedron,[BO_(3)]triangle and[TiO_(6)]octahedron.Adding B_(2)O_(3) to the system does not change the distribution of O—Si—O,O—B—O and O—Ti—O bond angles.With the addition of B_(2)O_(3),Si—O—Si and B—O—B bond angles rise from 156.12° and 148.43° to 158.17° and 157.08°,respectively.Most of the Ti—O—Ti bond angles distribute at 100.48°,and a small part of the Ti—O—Ti bond angles drop from 140.17° to 135.53°.With the increase of B_(2)O_(3) content,the proportion of B—O—M(Ca,Si,B and Ti)oxygen connections increase,the high coordination structure in the melt depolymerizes to low coordination structure,the overall polymerization degree of the system decreases,the self-diffusion coefficients of all ions increase,and the melt viscosity drops from 0.183 Pa·s to 0.140 Pa·s.